Polymerization in lyotropic liquid crystals. I. Change of structure during polymerization

Abstract

Abstract Polymerization was made at 60°C in a lyotropic liquid crystal of sodium undecenoate and water. The liquid crystalline structure prior to polymerization was identified by optical microscopy and low‐angle x‐ray diffraction as an array of hexagonal closely packed cylinders with the hydrophobic part of the soap in the center of the cylinders. During polymerization the structure became isotropic at 60°C. Cooling to 20°C transformed the structure to a lamellar liquid crystal–a reversible transition. The structure of the lamellar phase was interpreted as a polyethylene backbone from which deformed decanoate chains reached toward the aqueous layer. Molecular models showed the model to accept head‐tail, head‐head, and tail‐tail configurations in cis and trans conformations with the exception of the cis tail‐tail configuration.